Do you want to sell the tickets online or just track them online? Selling anything online will cost a reasonable merchant fee (usually around 3-4% plus 30 cents per transaction) if you are accepting credit cards. There is pretty much no way around this.
Paypal and Google Checkout will manage this for you.
I can live with only using the software to track orders and print tickets. Most of the tickets are sold in cash, anyway, and we have a credit-card solution already.